Purpose-built sequential gear boxes are known, but are much more expensive than standard gearboxes. Further, known sequential gearboxes provide a comparatively slow gear-change:—the engine must be unloaded to change gear, and the car therefore decelerates for the period of the gear change, (typically about 0.1 sec.), resulting in a loss of speed of the order of 3.5 kph.
It is therefore an object of the present invention to provide a gearbox adaptor which is capable of insertion into a standard gearbox to convert it to a sequential gearbox, the combination of providing a sequential gearbox in which gear changes can be made rapidly (typically 0.02 sec.) and at full throttle, so that the car does not lose speed during a gear change.